Merge pull request #380 in ZP/z-push from ~C0D3Z3R0/z-push:feature/ZP-1058-autodisc-failed-auth-ip to develop

* commit '81c868b5':
  ZP-1058 autodiscover: Fix mistake: always send response
  ZP-1058 autodiscover: Rework exception handling to match z-push core.
  ZP-1058 autodiscover: Print IP to log on failed authentication for usage with e.g. fail2ban